The Commonwealth was the republican government which ruled first England and then the whole of Britain and Ireland during 1649 - 1653 and 1659 - 1660. The term is also loosely used to describe the system of government during the whole of 1649 - 1660, the years of the Interregnum[?], although during 1653 - 1659, the government is properly called The Protectorate and took the form of direct personal rule by Oliver Cromwell, the Lord Protector.
... of Dáil Éireann and President of the Republic sites.
Some Biographies of former Taoisigh & Presidents of the Executive Council
Tim Pat Coogan, Eamon de Valera
John ...